Introduction
Let us read the following examples and understand the basic concept behind
Sanjay from Mumbai says “it is very cold today in Pune”, while Vinay who is from Pune says, “no, it is not cold, it is a perfectly normal temperature”.
Ashok while drinking his morning tea says, “I cannot drink this, because it is too hot”. Madhu, however, says, “Ye hot tea hai?”
The TV Weather Report show us today’s temperature in different cities of the State / Country along with the minimum and maximum temperatures recorded in the day
Doctor says, “Sanju has a very high fever of 104 degrees”.
These examples tell us the following
Hotness or coldness is a relative term
Higher Temperature corresponds to hotter conditions.
The lower the temperature, the cooler it is.
History
It will be certainly interesting to know the history of the concepts of Heat
Before later part of 18th century Heat was thought to be a fluid called Caloric
In 1798 Count Rumford suggested that heat is produced in mechanical operation. In 1799 Sir Humphrey Davy melted two pieces of ice by rubbing them together in a container at a temperature below the freeing point of water. In 1847 Herman Helmholtz stated that heat is a form of energy. In 1848 James Prescott Joule established the equivalence of heat and mechanical work as two forms of energy.
Think
When we visit a place like Simla, we shiver and try to use warm clothes. But, even small children in the local area of Simla are seen moving about without warm sweaters. Why does this happen?
It happens because, out body gets acclimatized to the temperature over a period of time.
Even in our homes, the infants and old people feel the changes in temperature as their bodies are sensitive. Young people, though face the same temperature variations, are able to sustain the warm or cold temperatures because their bodies are more tolerant.
A person who comes home after spending some time in the sun wants to sit under the fan whereas, the family members who are already in the house do not feel the need to use fan.